Innate Immunity Definition
The level of immune protection with which an individual is born. Researchers believe innate immunity, also called natural immunity, is the result of genetically encoded PATHOGEN recognition-that is, gene-regulated ability to identify and mount an IMMUNE RESPONSE to neutralize certain bacteria , viruses, and other substances capable of causing INFECTION or otherwise doing harm to the body.
The immune cell receptors recognize key characteristics of molecular structure common to many pathogens, called pathogen-associated molecular patterns (PAMPs), rather than specific pathogens. Their response does not require prior exposure before activation; thus PAMPs respond immediately to the presence of pathogens that fit the pattern. Innate immunity is species specific, which is why most infections cannot pass from one species to another. Pathogens capable of infecting multiple species are those that mutate for each species.
For further discussion of immunity within the context of the structures and functions of the immune system, please see the overview section “The Immune System and Allergies.”